An orthogonal frequency division multiplexing (OFDM) technology is used in a Long Term Evolution (LTE) system. In the LTE system, an uplink resource is allocated at a granularity of a transmission time interval (TTI). A length of one TTI is 14 OFDM symbols, that is, one subframe, and a length of one TTI is 1 ms. In uplink transmission of the LTE system, a base station instructs, by using an uplink grant (UL grant) included in a downlink control channel, user equipment (UE) to send data information on an uplink shared channel (PUSCH) in a corresponding uplink subframe. There is a fixed time sequence relationship between a UL grant and a PUSCH scheduled by using the UL grant. A PUSCH scheduled by using a UL grant included in a downlink control channel in an nth subframe (denoted as subframe # n) is in an (n+4)th subframe (denoted as subframe # n+4). A frequency domain resource occupied by the scheduled PUSCH is indicated by resource allocation (English: Resource Allocation, RA) information carried in the UL grant.
Conventionally, each PUSCH in LTE can be scheduled only by using one UL grant that has a fixed time sequence relationship with the PUSCH. Therefore, when an uplink service requirement is greater than a downlink service requirement, the base station needs to carry only a small amount of downlink data, but the base station needs to configure a large quantity of downlink subframes to schedule sufficient PUSCH resources by using a UL grant. Consequently, time domain resources are wasted, and a listen before talk (LBT) channel access mechanism needs to be performed frequently. If the LBT fails, the UL grant cannot be sent, and an uplink PUSCH cannot be scheduled either, thereby limiting a channel access opportunity. In addition, because of a constraint of the fixed time sequence relationship of the UL grant, the base station cannot schedule a further uplink subframe. Therefore, how to support efficient uplink transmission on an unlicensed spectrum when uplink and downlink services are unbalanced is a problem to be urgently resolved.
In the prior art, scheduling of a plurality of subframes is introduced in enhanced licensed-assisted access (eLAA). A base station device may send a plurality of UL grants in one downlink subframe, and schedule a plurality of consecutive uplink subframes by using one UL grant. In this way, a channel resource waste caused by frequently sending a UL grant can be reduced, and a further UL subframe can be scheduled because timing of the UL grant is flexible. However, in the prior art, a minimum UL grant scheduling delay is 4 ms (the delay is used by the UE to receive and detect the UL grant and perform packet encapsulation on a PUSCH sent on an uplink resource indicated by the UL grant). Therefore, when a downlink burst is less than four subframes, an idle gap still exists between the downlink burst and a scheduled uplink burst, and the UE cannot perform uplink transmission in the idle gap. Consequently, channel resources cannot be efficiently used.